SRAM is used in the semiconductor and computer industries because of the combination of speed, low power, and no requirement for refresh. Information can be written into and read out of an SRAM cell faster than with a dynamic random access memory (DRAM) cell, because the transistors of an SRAM cell can be switched faster than capacitors can be charged and drained. A typical SRAM cell includes two or more cross-coupled drive transistors and access transistors that control access to the drive transistors via a word line. Some SRAM cells use two access transistors and four drive transistors, and these SRAM cells are known as 6T cells. Other SRAM cells use two access transistors and two drive transistors, and these SRAM cells are known as 4T cells. 4T SRAM cells have gained favor because they require less physical space (per unit of memory) than 6T SRAM cells.